thermal: sun8i: Add hwmon support

Expose sun8i thermal as a HWMON device.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191228171904.24618-1-tiny.windzz@gmail.com

drivers/thermal/sun8i_thermal.c

@@ -20,6 +20,8 @@
 #include <linux/slab.h>
 #include <linux/thermal.h>
 
+#include "thermal_hwmon.h"
+
 #define MAX_SENSOR_NUM	4
 
 #define FT_TEMP_MASK				GENMASK(11, 0)
@@ -471,6 +473,10 @@ static int sun8i_ths_register(struct ths_device *tmdev)
 							     &ths_ops);
 		if (IS_ERR(tmdev->sensor[i].tzd))
 			return PTR_ERR(tmdev->sensor[i].tzd);
+
+		if (devm_thermal_add_hwmon_sysfs(tmdev->sensor[i].tzd))
+			dev_warn(tmdev->dev,
+				 "Failed to add hwmon sysfs attributes\n");
 	}
 
 	return 0;